1. Field of the Invention
The present invention relates to a method of fabricating an organic thin film transistor (OTFT) using surface energy control, and more particularly, to a method of fabricating an OTFT that can minimize leakage current and has high field effect mobility and low turn-on voltage by controlling surface energy of a gate insulating layer.
2. Discussion of Related Art
An OTFT is a device having at least one thin film layer made of an organic material. The OTFT can be processed at a low temperature, can employ a substrate made of plastic, etc., which is lightweight and flexible, and is inexpensive to produce. Thus, the OTFT has drawn attention as next-generation electronic device technology. In particular, with increasing demand for thin and lightweight displays, flexible OTFT and array technology are coming into the spotlight.
FIGS. 1A and 1B are cross-sectional views of OTFTs having a bottom-gate structure. FIG. 1A illustrates a top-contact structure, and FIG. 1B illustrates a bottom-contact structure.
Electrical characteristics of the OTFTs are greatly influenced by interface characteristics between a gate insulating layer 130 and a semiconductor channel layer 150, which play a crucial role in determining leakage current, field effect mobility, turn-on voltage, and so on.
Since the characteristics of the gate insulating layer 130 greatly effect the growth process of the semiconductor channel layer 150 deposited on the gate insulating layer 130 and thin film characteristics, the interface characteristics between the gate insulating layer 130 and the semiconductor channel layer 150 are very important.
For this reason, a method of improving characteristics of the semiconductor channel layer 150 to be deposited on a surface by performing plasma processing on the surface, or forming a self-assembled monolayer (SAM) that has a three-dimensional alignment property, has been disclosed.
However, the OTFT does not yet satisfy requirements for practical use, such as low leakage current, high field effect mobility, low turn-on voltage and high durability, and thus its use so far is limited.